I want to enlarge a photograph taken on Ilford Delta 100 pro film - I was wondering if it was OK to enlarge the print beyond 8x12" i.e to 10x16" perhaps.... is there noticeable loss of sharpness and what is the grain like? Anyone with personal experiences?

Jin,
as long as the negative is sharp, you should do OK with a 10x16. I've enlarged 35mm delta 100 to 11x14 inch prints and the grain was not excessive. every degree of enlargement softens the image; it really depends on what your personal levels of comfort are.
Take care,
Tom

hi
ilford delta is optimized for reletevly big enlargements (20x24'' or something around x17). there are some factors to be taken in order to make highh quality enlargement:
- critically good focused image
- very well exposed and developed negative. note, here the creatitivity and taste plays a very big part. so,some of the combinations u may like cannot be optimized for such a big enlargements. u have to try and experimante.
since u loose the contrast in greater magnification i will be forced to develop longer or to use harder paper. u have to find the correct balance for u. there is selenium toning for the negative which can help very much. note, it is not a magic but if u know to control the process it will add u very much ( more contrast and creaspy detail definition without increasing or changing the grain pattern.)
- the enlarging lense u use is of critical importance. popular nikons (which are very good) meoptas low price schniedrs and rodens are not for this job. most of them are optimized at around x10. even the componon-s is not the best choice but close with its roden competitor. there is rodenstok lense which is specially optimized for those cases but i dont use them - price!
hope it will help u for the next time
good luck.

Good processing technique really helps. Remember that the smallest scratch, flaw or dust particle will be magnified in the enalrgement. Very important to wash film thoroughly, dry in a dust free environment and clean and remove dust proir to printing. I know that this is common sense, but a 35mm neg enlarged to 10x16 will show many more flaws then 8x10 or 5x7.